1. Field of the Invention
This patent application concerns a gas refill and discharge valve for high pressure gas cylinders. The valve according to the invention is designed to resolve the problem of refilling gas cylinders used in fixed fire extinguishing systems, namely those installed in offices or buildings which are activated automatically following transmission of a signal by sensors placed in the areas monitored.
2. Description of Related Art
These extinguishing systems generally consist of a bank of large argon filled cylinders each having a capacity of 140 liters, filled at a pressure of 200 bar. It being evident that the larger the area monitored, the higher the number of cylinders used will be.
In consideration of the above, the new high rate discharge valve has been designed with two separate openings, one for discharging and the other for refilling gas so that the empty cylinders can be refilled quickly and easily without disconnecting the valves from the gas discharge hose.
Each cylinder is fitted with a high rate discharge valve opened by means of actuators controlled by the signal received from the above peripheral sensors.
The major problem related to these systems is refilling the cylinders once the extinguishing gas has been discharged in that this operation is carried out at refilling centres to which the cylinders are transported.
Attention is drawn to the fact that the bank of cylinders is part of a fairly delicate fixed system consisting of equipment, piping and instruments which cannot be transported so that the system must first be disconnected from the empty cylinders and then reconnected to the refilled cylinders; for safety reasons the system must be controlled and tested carefully whenever the cylinders are removed and replaced.
Moreover, the empty and refilled cylinders must be transported carefully with appropriate means in that during transport there is the risk of damaging delicate components of the cylinders such as the above mentioned high rate discharge valves, the pressure gauges or the threaded bronze connections.
Transport of the cylinders is thus not only difficult but may also be dangerous for the operators in view of the weight of the cylinders and the high pressures involved which in fact render all the various operations hazardous.
The high rate discharge valves currently available on the market do not permit refilling the cylinders without disconnecting the same from the gas discharge hose in that said valves are provided with a single opening through which the argon gas is discharged and refilled.
A valve of the type mentioned above is described in U.S. Pat. No. 3,860,073. In said patent the valve has the connection designed both for refilling the cylinder and to actuate the discharge of the fire extinguishing system. In order to refill, with this type of valve it is necessary to disconnect the manual/electric actuator, connect the refilling connector and refill all the cylinders; in addition, since said valve is designed for two-phase fluids, it is necessary to first connect the refilling pipe of the fluid in its liquid state and then the nitrogen pressurisation pipe. By means of all these the automatic fire extinguishing system is totally shut down since all the actuators are dismounted from the pilot cylinders.
In consideration of the above, the new high rate discharge valve has been designed with two separate openings, one for discharging and the other for refilling gas so that the empty cylinders can be refilled quickly and easily without disconnecting the valves from the gas discharge hose.
This would indirectly make it possible to refill the cylinders on site, namely in the same room where the bank of cylinders is installed, obviously by providing a network of auxiliary piping therefor through which the cylinders are supplied; in other words said auxiliary system will on one hand be supplied from a point outside the storage room accessible to the refilling tanker and on the other will supply each individual cylinder whose high rate discharge valve will be connected permanently both to the refilling system and to the extinguishing system.
Refilling can therefore be carried out without removing and transporting the cylinders but simply by opening and closing the valves.
Although the valve according to the invention operates like a standard high rate discharge valve, the new valve is characterised by the fact that the following three sections, which in standard valves are grouped into a single section, have been physically separated:
gas discharge section;
pressure intake section for the installation of pressure gauges and pressure switches for detecting the lack of minimum pressure conditions;
refilling section.
For major clarity the description of the valve according to the invention continues with reference to the enclosed tables which are intended for purposes of illustration and not in a limiting sense, whereby: